TheLEED for Homes Rating System (v4)includes theWater Efficiency (WE) Credit: Outdoor Water Use
, which awards points based on the ratio of turf grass (high water use) to native or adapted plants (low water use) in the softscape to reduce irrigation needs.
According to theLEED Reference Guide for Homes Design and Construction (v4):
WE Credit: Outdoor Water Use (1-4 points)
To achieve 3 points, the softscape must have less than 20% turf grass and more than 75% native or adapted plants, calculated by area.
Source: LEED Reference Guide for Homes Design and Construction, v4, Water Efficiency Credit: Outdoor Water Use, p. 98-99.
TheLEED v4.1 Residential BD+Crating system confirms:
WE Credit: Outdoor Water Use
For 3 points, the turf grass area must be less than 20% of the total softscape, and the native or adapted plant area must exceed 75%.
Source: LEED v4.1 Residential BD+C, Credit Library, accessed via USGBC LEED Online.
Calculation:
* Total softscape area: 57,500 ft² (5,342 m²).
* Turf grass area: 8,000 ft² (743 m²).
* Turf grass percentage: (8,000 ÷ 57,500) × 100 = 13.91% (< 20%, meets requirement).
* Minimum native or adapted plant area for 3 points: > 75% of 57,500 ft² = 0.75 × 57,500 =43,125 ft².
* Compare options:
* A. 38,967 ft² (3,620 m²): 38,967 ÷ 57,500 = 67.77% (< 75%, does not meet).
* B. 39,355 ft² (3,656 m²): 39,355 ÷ 57,500 = 68.44% (< 75%, does not meet).
* C. 43,126 ft² (4,007 m²): 43,126 ÷ 57,500 = 75.00% (meets > 75% requirement).
* D. 2,784 ft² (259 m²): 2,784 ÷ 57,500 = 4.84% (far below 75%, does not meet).
The correct answer is43,126 ft² (4,007 m²) of native or adapted plant area(Option C), as it meets the minimum requirement for 3 points.
TheLEED AP Homes Candidate Handbookemphasizes WE credits, including outdoor water use, and references theLEED Reference Guide for Homes Design and Constructionas a key resource. The exam is based onLEED v4, ensuring the relevance of the table's criteria.
References:
LEED Reference Guide for Homes Design and Construction, v4, USGBC, Water Efficiency Credit:
Outdoor Water Use, p. 98-99.
LEED v4.1 Residential BD+C, USGBC LEED Credit Library, accessed via LEED Online (https://www.
usgbc.org/credits).
LEED AP Homes Candidate Handbook, GBCI, October 2024, p. 12 (references study resources and exam scope based on LEED v4).
USGBC LEED for Homes Rating System (v4), available via USGBC website (https://www.usgbc.org
/resources/leed-homes-design-and-construction-v4).
LEED v4.1 for Homes, USGBC, accessed via LEED Online, confirming softscape ratios.